Piston



Sept. 4, 1923.

A.r BRYNTESON PISTON Filed April 17. 1922 24 isf-'2 (6 @i Hi /////////////////////////////v////A/,"//.'// E" rrr e ALFRED BRYNTESON, 0F ST. FUL, MINNESOTA.

rrs'roia Application led April 17, 1922; Serial N'o. 554,259.

To all 'whom t 'may camera:

Be it known that ALFRED a citizen of the United States, residing at St. Paul, in the county of Ramsey and State of Minnesota, haveinvented certain new and useful improvements in Pistons, of which the following is a specification.

My invention relates to piston constructions for internal combustion engines, as an article of manufacture, and has for its object to reduce the weight of the piston without sacriicing strength and durability.

A further object of the invention is to reduce the cost of production by providing features of construction whereby a piston may be built up of cast metal such as aluminum and ductlle steel to form a composite compact unit which will be reinforced by the steel at important points in the structure.

It is a further object of the invention to provide a steel supporting base around which the aluminum parts are cast, which may be formed of ordinary steel tubing, suitably indented at points so as to form integral reinforcing members whereby the ori inalv strength of the tubing is retained.

her objects of theV invention will appear throughout the specification, the invention consisting in the novel construction, combination andl arrangement of parts hereinafter to be described and claimed.

In the drawings forming part1ot this specification Figure 1, is a side elevation of a piston shown partly in section embodying my invention.

Fig. 2 is a sectional view online 2-2 of Fig. 1, a part thereof being broken away.

Fig. 3 is a sectional view on line 3-3 oi Figs. 1 and 2.

i is a perspective view of the steel portion or the piston.

Fig. 5, is a side elevation of Fig. 4C, partly broken away.

Fig. 6, is a sectional view on line 6-6 'of Fig. 5.

Fig. 7, is a sectional view on line 7--7 of Fig. li, showing the core therein,

Fig. 8 is a sectional view on line 8-8 of Fig. 4, and

Fig. 9, is a sectional view on line 9-9 of Fig.

The' invention comprises a soft steel shell portion 1, and a cast'portion 2. The shell portion comprises a cylindrical or tubular BnYN'rEsoN,

body portion 3, of relatively heavy tubing of euniform diameter, which forms the mager portion of th shell; and a reduced recessed portion 4, concentric with said body portion and preferably welded or fused thereto. The body portion is formed with parallel ends 5 and 6, and with oppositely disposed indents 7, preferably spaced 'slightly from the end 6 thereof.

The indents are formed by cutting the wall of the tube transverselyy at 8 and 9,

and bending inwardly the metal therebe-l tween to form two opposite flat reinforcement bands or supports 10, preferably parallel to each other, the flat surfaces thereof being somewhat larger than the diameter of the usual wrist pin (not shown). The wrist pin journal or bore 11, extends radially at right angles to the longitudinal axis of the piston, and extends through the reinforcing parts 10.

Positioned concentrically on the upper end 6 of the body portion is the reduced portion 4, the latter being formed with an upper and lower radial iiange 12 and 13 respectively. The upper iange is somewhat vsmaller in diameter than the diameter of the body portion, while the shell or circumferential wall 13 between the two flanges, is somewhat smaller' in diameter vthan the inner diameter ot the body portion, whereby is formed the annular internal offset 14 and the outer annular recess 15. 'lhe shell 13 is cut away on opposite sides at a point in vertical alinement with the indents 7 to form openings 16, and intermediate said openings, on opposite sides to form the openings 17. These openings extend between the flanges 13 and 12 andare preferably vertically elongated. The flange 13 is perforated at intervals by the openings 17 rThe recessed portion 11i is pret erably spot welded to the body portion, though it may be secured thereto in any other suitable manner.

-While have shown the shell formed of two parte welded together, it is to be under stood that the shell may be constructed of a single piece of tubing and formed in a die to reduce its upper end as shown in the drawings.

ln Figure 1, 18 designates cast aluminum or other suitable material which is cast in the usual manner around the removable core 18', which latter tits the inner diameter of the body portion and is formed with lOl) suitable cavities to mold the wrist pin bearing blocks 19. The cavities in the core are sufficiently large to cause the metal to embed the reinforcing bands 10, and, also, to form a flat inner surface 19 arallel with the flat surface of the reinforcing members: As shown in Figs 1 and 2, these reinforcing members are entirely embedded including the lower edge thereof.

As best shown in Figure 4, the molten metal in the process. of casting, will pass through the openings 20 above and below the reinforcing bands 10, to thereby fill the cavity 7 The metal will also fiow through the openings 16 and 17 and fill the annular recess 15 to bring the metal flush with the outer diameter of the body portion.

The mold is also formed to cast a top wall 21 to form the top of the piston which latter4 will completely embed the fiange 13 as shown in Figs. 7 and 8. For the purpose of reinforcing the top wall 21 the cross ribs 22 on the underside of the wall are provided, said ribs registering with the openings 16 and 17 and extending down the inner side of the shell 13'..

As shown in Fig. 9, the ribs on the inner side of the shell form integral keys, whereby the cast metal is interlockingly anchored to the shell. That part of the rib 22 which extends to the bearing blocks 19 merges with the latter to form the longitudinal ridge 23. Thus, the top wall of the piston is firmly cast around the fianges 13 and 12, and anchoredin the openings 16 and- 17 of the shell. The piston may now be machined in the usual manner, the piston ring grooves 24 being Wholly contained within the annular recess 15 while the flange 13 forms a reinforcement for the cast metal above the first groove. The bore 11 for the wrist pin, as stated in the foregoing, ex

tends through the reinforcement parts 10, which latter provide stiffness and strength where it is most needed. By havin the ange perforated as by the openings 1 the cast metal is firmly anchored in the flange, the latter serving as a reinforcement and a stiffening member. By constructing the piston of ductile steel and cast Imetal as described, I am enabled to make the body portion of the piston much thinner than would be permitted if cast iron or aluminum yield. The strip E may be severed before casting if desired as indicated at c in Figure 6, when the openings 17 would constitute notches in the edge of the flange.

I claim:

1. A piston, comprising a tubular soft steel shell portion having indents in opposite sides thereof, said indents having openings in communication with the interior' of said shell portion, and a cast metal portion forming the top of the piston, saidl cast portion`extending downwardly` at 0pposite sides and filling said indents and extending through said openings and conipletely embedding the inner side of said indents to thereby form wrist pin journal blocks.

2. A piston having a plurality of piston ring grooves comprising a tubular soft steel body portion open at the ends and an externally recessed portion secured concentri` cally to the top thereof, openings spaced at intervals in the circumferential wall of the through and beyond said opening, the lower side of said recessed portion defining the major circumferential portion of the lower internal border of said cast metal portion, for the purpose set forth.

3. A piston comprising a tubular 'soft steel shell portion open at the ends having a relatively wide annular external recess adjacent the top thereof, oppositely disposed openings in the wall of said recess, a cast metal portion, forming the top wall of the piston and vextending into said annular recess to completely fill the latter and extending interlockingly inwardly through Said openings and downwardly beyond said-recess to 'form wrist pin journal blocks, and opposite reinforcing members integral with said body portion embedded one in each of said journal blocks.

4. A piston comprising a cylindrical soft steel shell portion open at the ends, the major portion of said shell being larger in diameter than the minor portion thereof, a radial fiange at the outer end of the minor portion, said flange somewhat smaller in diameter than the major portion of the shell, and a cast portion of the diameter of said major portion cast around said minor portion and across the top thereof so as to grholly embed said radial fiange for the purpose set forth.

5. A piston, having piston ring grooves adjacent the top thereof, said piston being formed of-a cylindrical shell made of ductile steel extending beyond the piston ring grooves, said shell having a radial fiange at its upper extremity for-med with openings occupying the major portion of the width of latter and extending downwardly therefrom the flange for the purpose set forth. to solely form the major portion of that part 6. A piston of the class described, eomof the piston below the piston ring grooves. 10.

prising a cast top portion having peripheral I n testimony whereof I alx my signa- 5 piston ring grooves adjacent the top thereof, ture.

and a soft steel shell portion partially embedded in said cast portion to reinforce the i ALFRED BRYNTESON. 

